All categories

3 years ago

A pulley system has an efficiency of 74.2%. If you perform 200 J of work, how much useful work does the pulley perform?

1 answer:

7 0

Efficiency is the measure of how efficient a process is. It is used to assess the ability of a process in avoiding waste energy, materials, money and time in doing a desirable output. It is calculated as;

Efficiency = useful energy ouput / total energy input

.742 = useful energy / 200 J
Useful energy = 148.4 J <-----------OPTION B

You might be interested in

Who was the discoverer of the neutron

Pavel [41]

Answer:

James Chadwick

Explanation:

In May 1932 James Chadwick announced that the core also contained a new uncharged particle, which he called the neutron

6 0

2 years ago

Read 2 more answers

A girl hits a baseball with a bat. When the bat strikes the ball, what is the

Illusion [34]

Answer:

Its simple! B The ball accelerates upward!♡♡

5 0

3 years ago

Read 2 more answers

Starting from zero, the electric current takes 2 seconds to reach half its maximum possible value in an RL circuit with a resist

Leno4ka [110]

Answer:

time=4s

Explanation:

we know that in a RL circuit with a resistance R, an inductance L and a battery of emf E, the current (i) will vary in following fashion

$i(t)=\frac{E}{R}(1-e^\frac{-t}{\frac{L}{R}})$ , where $i$ max= $\frac{E}{R}$

Given that, at i(2)= $\frac{imax}{2} =\frac{E}{2R}$

⇒ $\frac{E}{2R}=\frac{E}{R}(1-e^\frac{-2}{\frac{L}{R}})$

⇒ $\frac{1}{2}=1-e^\frac{-2}{\frac{L}{R}}$

⇒ $\frac{1}{2}=e^\frac{-2}{\frac{L}{R}}$

Applying logarithm on both sides,

⇒ $log(\frac{1}{2})=\frac{-2}{\frac{L}{R}}$

⇒ $log(2)=\frac{2}{\frac{L}{R}}$

⇒ $\frac{L}{R}=\frac{2}{log2}$

Now substitute $i(t)=\frac{3}{4}imax=\frac{3E}{4R}$

⇒ $\frac{3E}{4R}=\frac{E}{R}(1-e^\frac{-t}{\frac{L}{R}})$

⇒ $\frac{3}{4}=1-e^\frac{-t}{\frac{L}{R}}$

⇒ $\frac{1}{4}=e^\frac{-t}{\frac{L}{R}}$

Applying logarithm on both sides,

⇒ $log(\frac{1}{4})=\frac{-t}{\frac{L}{R}}$

⇒ $log(4)=\frac{t}{\frac{L}{R}}$

⇒ $t=log4\frac{L}{R}$

now subs. $\frac{L}{R}=\frac{2}{log2}$

⇒ $t=log4\frac{2}{log2}$

also $log4=log2^{2}=2log2$

⇒ $t=2log2\frac{2}{log2}$

⇒ $t=4$

5 0

3 years ago

In a lab, a block weighing 80 N is attached to a spring scale, and both are pulled to the right on a horizontal surface. Frictio

notka56 [123]

Thank you for posting your question here at brainly. I hope the answer will help you. Feel free to ask more questions.

There should be an image that should accompanied your question, I was able to chcek it from other sources. the acceleration of the block when the scale reads 32N is 4.0 m/s*s

5 0

2 years ago

Read 2 more answers

On a flat surface, a moving bicycle has _____ energy than a stationary car. A. less kinetic B. more kinetic C. less potential D.

Marina86 [1]

On a flat surface a moving bicycle has more kinetic energy than a stationary car

3 0

3 years ago

Read 2 more answers